Issue link: https://te.mouser.com/i/1350754
Predictive Maintenance with Vibration Sensors TE CONNECTIVITY SENSORS / WHITE PAPER PAGE 5 Frequency Response The frequency response of the two accelerometers were tested on a SPEKTRA GmbH CS18 HF high frequency calibration shaker with a range of 5Hz to 20KHz. The sensors were securely mounted to ensure accurate results over the full test range. Three sensors of each technology, PE and MEMS VC, were tested to ensure the results were consistent. The results of the testing are illustrated here. A maximum ±1dB amplitude deviation is assumed as the usable bandwidth although a tighter deviation of ±5% is often used for bandwidth tolerance. The data indicates that the VC MEMS sensor has a usable bandwidth up to 3KHz while the Piezoelectric sensor has a usable bandwidth >10KHz (this particular PE sensor was within specification up to 14KHz). It is worth noting that the low frequency cut-off for the PE sensor was at 2Hz while the MEMS sensor has a response down to 0Hz since it is a DC response device. Measurement Resolution and Dynamic Range To determine the measurement resolution and dynamic range of the piezo-electric and VC MEMS sensors, the samples were tested in a noise isolated chamber with state-of-the-art measurement equipment capable of micro-g measurement resolution. The units were installed in same chamber and tested at the same time to eliminate any errors from outside environment interference. The measurements were conducted at four distinct bandwidth settings and the residual noise was measured at each setting. The results are detailed in table below. The measurement resolution and dynamic range were calculated based on a 0.03-10KHz bandwidth and are detailed below. The resolution of the PE sensors is ~9x better than the VC MEMS sensors. This results in a significantly better dynamic range which enables end user to detect potential problems at a much earlier stage. Resolution Residual Noise Spectral Noise Dynamic Range Resolution Model mg-rms µV-rms µg-rms/√Hz dB bit PE #1 1.4 57.6 14.4 88 14.6 PE #2 1.4 56.3 14.1 88 14.6 MEMS #1 12.5 498.2 124.6 69 11.5 MEMS #2 13.3 532.1 133.0 68 11.4 MEASUREMENT RESOLUTION COMPARISON Model 0.03~300Hz µV-rms 0.03~1KHz µV-rms 0.03~3KHz µV-rms 0.03~10KHz µV-rms PE #1 27.2 30.8 39.5 57.6 PE #2 25.1 31.7 38.6 56.3 MEMS #1 377.6 405.2 412.7 498.2 MEMS #2 415.7 430.2 453.9 532.1 RESIDUAL NOISE COMPARISON AT VARIOUS BANDWIDTH